Although the controversy regarding Gen 8 Pokemon games' Pokedexes subsided when The Pokemon Company announced an Expansion Pass for Pokemon Sword and Shield, many iconic pocket monsters are still missing on the Switch. Among the most beloved missing monsters are the starters from Generations 5 and 6, alongside some forgotten Pokemon like Skiddo and Gogoat from X and Y, which is something Pokemon Scarlet and Violet will hopefully fix. Still, with 60 Pokemon missing from all Switch-based entries, it's likely not all of them will return in Gen 9 - especially not in the base game, considering its Pokedex might be the same size as that of Gen 8.
On the other hand, there may be reasons why these critters are not yet returning, as The Pokemon Company might be working on new Pokemon: Legends games or remakes for Gen 5. Pokemon Black and White are next in line for a remake in the franchise, but with Gen 9 on the horizon, it's hard to predict whether these will come in the near future or not. If they do come, it's possible that Gen 6 remakes are also in the pipeline, with a release date that's probably sometime after Gen 10. These Gen 5 and 6 remakes might be why some Pokemon have not yet returned to the franchise.
Why Gen 5 and 6 Remakes Might be in the Pipeline
A popular theory is that some of these critters did not get back to the Switch because they were too powerful in their respective generations, and thus they could similarly unbalance the modern games. Examples of this include Greninja and Eelektross, which were incredibly powerful on release for different reasons. Eelektross is a pure Electric-type that could have Levitate as its ability, meaning it would effectively have no weaknesses and still deal super-effective STAB damage to both Water and Flying-type Pokemon.
Meanwhile, Greninja was one of the most popular pocket monsters in Pokemon X and Y, even appearing successfully in multiple tournaments due to having its own sort of Mega Evolution equivalent thanks to Ash Greninja. Then again, The Pokemon Company brought back popular tournament monsters like Landorus in Gen 8, so there are ways it could handle the return of Pokemon such as Greninja and Eelektross.
Because some missing critters were and still are popular, it's possible Nintendo wants to take advantage of that in the future when Gen 5 and 6 remakes are announced. Although the Oshawott line did return in Pokemon Legends: Arceus, it's still plausible that if Pokemon Scarlet and Violet don't include the remaining Gen 5 starters, it's because they are going to be part of the Pokemon Black and White remakes that may similarly come to Switch if no new console is announced by then.
All of this makes one wonder if Nintendo actually wants to keep the Switch as its main console for several years to come, instead of exploring other options for consoles. Pokemon Brilliant Diamond and Shining Pearl came out last year, and with Pokemon Scarlet and Violet coming in less than four months, it seems logical that Pokemon Black and White remakes are at least another full year away, if not more. Ultimately, if these monsters do end up being excluded from Gen 9 Pokemon games' Pokedex, it may very well be a sign that the next Pokemon remakes will come at some point soon.
